Internet and cellular networks are also being used to access and
view A/V media all over the home. The consumer wants to be able to move
A/V content easily from device to device and location to location, cost
effectively and in realtime or faster.

This requires the exchange of stored or viewed content between
devices within the home, or even outside the home, so it can be viewed
on alternative devices, at different times and even by different
consumers.

To achieve this, there is a need for adaptive devices that can
provide three primary functions:

This article discusses these important functions and how they can be
implemented with a single system-on-a-chip (SOC), such as Texas
Instruments' (TI) DaVinci family of processors. The processes involved
in a typical A/V media client and server application are either
deterministic (Ethernet, USB, FLASH, A/V Demux, A/V Mux), or
non-deterministic (video capture/display, audio capture/playback,
video/audio decode/encode).

The non-deterministic processes are aperiodic, and the deterministic
processes periodic. From an architectural standpoint, nondeterministic
and deterministic processes should not mix. Ideally, a host processor
should handle the non-deterministic processes with a digital signal processor (DSP)
serving as the coprocessor and performing the more computationally
intensive deterministic operations.

With this architecture, overall system throughput is high since the
nondeterministic processes are prevented from disrupting the DSP
processes.

This architecture becomes even more appealing as the amount of
processing increases, specifi cally for HD applications or when video
encoding is needed. To support this architecture, TI has developed the
DaVinci family of DSPs. Figure 1 below
shows the DM6446 in the DaVinci family, which has an ARM926 and a C64x
DSP.

Figure
1: DaVinci (DM6446) device block diagram

In this SOC, the internal DSP performs the deterministic
processes freeing up the ARM to handle the non-deterministic processes.
Here the flexible DSP architecture implements the transcoder operation
and provides a very good price/performance trade-off. With the DSP
implementing the algorithmically complex task of supporting different
compression formats, it allows the programmability needed to adapt to
future compression formats and software upgrades.